Alternating-current telephone.



PATENTED NOV. 24, 1903 A. PLEGHER. ALTBRNATING CURRENT TELEPHONE.

APPLICATION FILED FEB. 25. 1903.

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Patented November 24, 1903.

PATENT OFFICE;

ANDREW PLEOHER, OF BRISTOW, VIRGINIA.

ALTERNATl NG-CURRENT TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 745,292, dated November 24, 1903.

Application filed February 25, 1903. Serial No. 144,941. (No model.)

To (ZZZ whom it may concern:

Be it known that I, ANDREW PLECHER, of

' Bristow, in the county of Prince William and are connected by the line-wire A and either a return metalliecircuit A or a ground connection.

My invention comprehends for the transmitter two local batteries,two ind action-coils, and two double microphones operated by one or more diaphragms, one of which double microphones directs alternately-reversed impulses from the local batteries through the primary wires of the induction-coils, and the other of which double microphones directs the alternately-reversed impulses from the secondary wires of the induction-coils over the line, each microphone being simultaneously operated by a vibrating part common to them both.

B B are the two local batteries.

1 I are the two induction-coils.

O O are the double microphone for the primary circuits of the induction-coils.

0 0 are the double microphone for the secondary wires of the induction-coils, and D D are double diaphragmswhich simultaneously actuate the two microphones. The voice vibrations are supposed to pass between the two diaphragms and move them in opposite directions. This motion is made to vibrate a lever L, placed between the diaphragms. The diaphragm D has aconnection n with the lever L, and D has a connection n with the opposite side of the same lever. These two connections n n being at different levels, the movement of the diaphragms in opposite directions will make a deflection of the lever. This lever is carried down between two carbon spheres 0 C 01 and c o and pressed by rubber bands 7" and 'r against the opposite ends of the lever L.

The local battery B has its circuit made through the primary wire b of the inductioncoil I and thence through a wire 5 laid alongside of the lever L to a terminal button b, which rests against the carbon-sphere O, the other pole of this local battery B being connected to the wire 0, that is in electrical connection with and supports said carbon sphere O. The local battery B has its circuit made through the primary wire 17 of the inductioncoil 1 and thence through a wire b laid alongside the lever L to a terminal button Z1 which rests against the carbon sphere C the other pole of the local battery B being connected to the wire 0 that is in electrical connection with and supports the carbon-sphere C The two carbon buttons at the lower end of lever L are insulated from each other, and the batteries B B have opposite poles connected, respectively, to their two carbon spheres 0 C In like manner, the secondary wire a of induction-coil I is connected to a terminal button a resting against the carbon sphere C above, and the secondary wire a ofinductioncoil I is connected to a terminal button a resting against the carbon sphere C The connection with the upper spheres (3 C are both connected to the line A, and the secondarywires a a of the induction-coils are both connectedat G to the return circuit-wire A or the ground. At the receiving-point the line-wire A and return-wire A (or ground connection) connect with the similarly-wound coils of two magnets E and E, Whose like poles are nearest each other and between wires 0 cflwhich support and are in electrical which is a tongue diaphragm F, so that when 4 the ,opposite impulses of an alternating. current come over the line one magnet, E, is energized and the other, E, demagnetized to more energetically influence the vibration of the diaphragm F, the magnets E and E being each alternately energized and demagnetized according to the polarity of the impulses received.

The operation of my telephone is as follows: If the bottom end of lever L moves to the left, button 19 and sphere G are pressed into firmer contact, and contact between and O is lessened. Battery B will then control the line over primary circuit B b b b O c, and the secondary circuit of induction-coil I will be made over the line, as follows: a A

- through the remote receiving instrument and back by A to c 0 a to a. In this action it will be seen that the current passes for the primary on the left-hand side of the lever L for the lower microphone and for the upper microphone on the right-hand side of the lever for the secondary, since the upper and lower ends of the lever move in opposite directions at the same moment. This action we will suppose sends a positive impulse over the line, as shown by the positive arrows. Now if the lower end of lever L moves to the right then a negative impulse will be sent over the line, as shown by the negative arrows, as follows: When the lower end of the lever L moves to the right, the circuit of the other local battery B is made as follows: from B to c to C button b wire b and the primary b of the induction-coil 1 While the secondary a of the induction-coil I goes to button a (which is now thrown to the .left) and thence to sphere 0 supporting wire 0 line A to the distant receiving instrument, and back by wire A to ct again; but since the current of battery B passes through induction-coil I in the opposite direction from that in which the current from battery B passed through its induction-coil I it will be seen that the induced impulse on the line is reversed. As these vibrations of lever L and reversed impulses'on the line are of immense rapidity, so are the line impulses reversed with corresponding rapidity and the receiving-diaphragm F vibrated in unison by the simultaneous magnetization and demagnetization of the magnets E E of the receiver, which thus give a greater energy of vibration andamplitude of wave.

Instead of having two diaphragms D D to actuate the lever L it is obvious that the lever could be vibrated by a single diaphragm.

Having thus described my invention,what I claim as new, and desire to secure by Letters Patent, is-- 1. Atelephone-transmitter,comprising one or more diaphragms, a lever actuated thereby, two double microphones, two inductioncoils, and two local batteries, the primary circuits of each-induction-coil being made through one microphone, and the secondary circuits of the induction-coils being made through the other microphone substantially as described.

2. Atelephone-transmitter,comprising two diaphragms, an interposed lever connected to the diaphragms out of alincment, a double microphone for one end of the lever, a double microphone for the other end of the lever, two local batteries, and two induction-coils, the local-battery circuits being made through the primary wires of the two induction-coils and one of the double microphones, and the secondary circuits of the induction-coils being made through the other double microphones substantially as and for the purpose described.

3. A telephone-transmitter comprising one or more diaphragms, a lever actuated thereby, two double microphones, two inductioncoils, and two local batteries, the primary circuits of each induction-coil being made through one microphone, and the secondary circuits of the induction-coils being made through the other microphone; in combination with a receiving instrument arranged in the secondary circuits of the induction-coils and consisting of two similarly-wound electromagnets having like poles near each other and a vibrating diaphragm placed between said like poles and influenced by the simultaneous magnetization and demagnetization of the oppositely-placed ele'ctromagnets.

ANDREW PLECHER.

Witnesses:

- EDW. W. BYRN,

SoLoN C. KEMON. 

